Quality parameters and antioxidant and antibacterial properties of some Mexican honeys

A total of 14 Mexican honeys were screened for quality parameters including color, moisture, proline, and acidity. Antioxidant properties of complete honey and its methanolic extracts were evaluated by the DPPH, ABTS, and FRAP assays. In addition, the antimicrobial activity of complete honeys against Bacillus cereus ATCC 10876, Listeria monocytogenes Scott A, Salmonella Typhimurium ATCC 14028, and Sthapylococcus aureus ATCC 6538 was determined. Most of honeys analyzed showed values within quality parameters established by the Codex Alimentarius Commission in 2001. Eucalyptus flower honey and orange blossom honey showed the highest phenolic contents and antioxidant capacity. Bell flower, orange blossom, and eucalyptus flower honeys inhibited the growth of the 4 evaluated microorganisms. The remaining honeys affected at least 1 of the estimated growth parameters (increased lag phase, decreased growth rate, and/or maximum population density). Microorganism sensitivity to the antimicrobial activity of honeys followed the order B. cereus > L. monocytogenes > Salmonella Typhimurium > S. aureus. The monofloral honey samples from orange blossoms, and eucalyptus flowers demonstrated to be good sources of antioxidant and antimicrobial compounds. All the Mexican honey samples examined proved to be good sources of antioxidants and antimicrobial agents that might serve to maintain health and protect against several diseases. PRACTICAL APPLICATION: The results of the study showed that Mexican honeys display good quality parameters and antioxidant and antimicrobial activities. Mexican honey can be used as an additive in the food industry to increase the nutraceutical value of products.     

Synthesis,characterisation, antioxidant and antibacterial properties of p-hydroxybenzoic acid-grafted chitosan conjugates

In this study, p-hydroxybenzoic acid-grafted chitosan (PA-g-CS) conjugates with different grafting degrees were synthesised by free radical-regulated grafting approach. The obtained PA-g-CS conjugates were characterised by UV–Vis spectra, fourier transform infrared spectroscopy (FT-IR) spectra, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Results revealed that PA was successfully grafted onto the hydroxyl group and the amino group positions of CS. Compared with CS, PA-g-CS showed decreased crystallinity, thermal stability, as well as a loose and porous surface morphology. The antioxidant assays demonstrated that PA-g-CS exhibited remarkably enhanced 2,2-diphenyl-1-pyridohydrazino- and 2,2′-azino-bis(3-ethylbenzothiazoline-6)-sulfonic acid-scavenging activities in vitro. Similarly, the synthesised PA-g-CS also significantly increased the antimicrobial activities towards gram negative and positive bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Moreover, the products with a relatively higher grafting degree showed stronger biological activities. Our findings suggest that PA-g-CS conjugates have great potential application in the field of active packaging, antioxidants and preservatives.     

Evaluation of food grade antioxidant formulation for sustained antifungal,antiaflatoxigenic and insecticidal activities on peanut conditioned at different water activities

The aim of this study was to investigate antifungal and insecticidal activity of two microencapsulated antioxidants: 2(3)-tert-butyl-4 hydroxyanisole (BHA) and 2,6-di(tert-butyl)-p-cresol (BHT) against Aspergillus section Flavi and Oryzaephilus surinamensis (L.), a vector carrier of aflatoxigenic fungi on stored peanuts. Susceptibility of Aspergillus section Flavi, insects, and aflatoxin B₁ accumulation in sterile peanut kernels conditioned at two different water activities (a_w) (0.83 a_w and 0.95 a_w) was determined with different doses of antioxidant formulations (10, 20 and 30 mM) during 45 days. Moreover, Aspergillus section Flavi isolation frequency from live and dead insects was evaluated. The BHA formulation completely inhibited Aspergillus section Flavi development regardless of a_w and doses assayed. Antifungal effect of microencapsulated BHT was highly dependent on a_w, with 86–100% fungal inhibition at 20 and 30 mM, at the lowest a_w (0.83 a_w) and at the end of the experiment. No aflatoxin accumulation was detected in samples treated with the BHA formulation. In general, low levels of Aspergillus section Flavi were detected in dead insects. Our results show efficacy for 45 days, in addition microencapsulated BHT could be an alternative to control peanut pests in dry kernels.     

Physical, biochemical and antioxidant properties of some Indian honeys

The study was intended to characterise the physicochemical and antioxidant properties of some commercial brands of Indian honeys. All the samples showed considerable variations with reference to their level of total phenolics, protein, radical scavenging activity, ascorbic acid equivalent antioxidant content (AEAC) and ferric reducing antioxidant potential (FRAP). Comparative studies of Indian honeys indicated the strong correlation between proline content and AEAC as well as 2,2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity whereas phenol content was strongly correlated with FRAP values. Thus, overall antioxidant activity seems to be contributed by proline and phenol contents. Besides these major factors, colour pigments (ABS₄₆₀) were also found to contribute significantly to the overall observed antioxidant activity.     

Interaction of copper ion with some food dyes.

The nature of the complexes formed by Cu²⁺ with some food dyes has been studied spectrophotometrically under varied conditions. The results indicated formation of 1:1 metal: dye species at pH 4.5 and of 2:1 metal: dye species at higher pH. The latter result is unexpected and surprising since in most cases azo dyes form 1:1 or 1:2 metal: dye species and no example of a metal complex having more than one metal atom per dye molecule has so far been reported. This curious observation has been rationalised in terms of a salt forming Cu²⁺ ion and a coordinated Cu²⁺ ion per dye molecule; tentative structures for these species have also been proposed. It is hoped this novel finding will stimulate further investigations into the metal-dye complexes.     

一些天然防腐剂的抗菌效果

本文对一些天然防腐剂的抗菌效果进行了研究。荔枝精油中富含的环丙烷基脂肪酸能有效地防止微生物引起的肉类制品的变质。可使微生物的生长适应期延长4倍，对数生长期和稳定生长期缩短1／3。可有效降低微生物的生长势和减少做生物的生长量。     

Evaluation of antioxidant,antibacterial and anti-tyrosinase activities of four Macaranga species

The methanolic fresh leaf extracts of Macaranga gigantea, Macaranga pruinosa, Macaranga tanarius and Macaranga triloba were screened for their antioxidant properties (AOP), tyrosinase inhibition and antibacterial activities. Total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferric-ion reducing power (FRAP), ferrous-ion chelating (FIC) and lipid peroxidation inhibition (LPI) activities were used to evaluate the AOP. Modified 3,4-dihydroxy-L-phenylalanine (L-DOPA) method was used to determine tyrosinase inhibition activity, whereas antibacterial activity was determined using the disc-diffusion technique. TPC screening of the same species from different collection sites showed no significant difference between sites. M.triloba showed the highest ascorbic acid equivalent antioxidant activity (AEAC), FRAP and LPI values. M. tanarius, which showed the lowest TPC, AEAC, FRAP and LPI activities, exhibited the best FIC activity. M. pruinosa showed the best tyrosinase inhibition activity, whereas M. triloba showed the best antibacterial activity against Gram-positive bacteria species, with minimal inhibition dosage (MID) values as low as 10 μg/disc.     

The impact of ultrasound decrystallization on enzymatic,antioxidant and antibacterial properties of honey

The aim of the research was to assess the impact of liquefying honey by ultrasound processing on its biological activity. Four solid honey samples of different botanical origin were decrystallized by using the ultrasound (sonic bath, 40 kHz, 800 W) and conventional thermal processing (water bath, 40 °C). The biological properties of liquefied and control solid honeys were compared. The ultrasound processing significantly shortened the time of honey liquefaction (from 24 h to 15 min) and delayed of the re-crystallization process compared to conventional method (from 1 to 4 months). Diastase number was comparable in ultrasound and unprocessed honeys, but decreased in conventionally liquefied samples (by 8 to 20.6%) whereas the activity of α-mannosidase and β-galactosidase was insignificantly affected only. Growth inhibition of S. aureus and E.coli by 12.5% water solution of control honey samples was variety-dependent, the lowest for rape (12 and 19%) and the highest for honeydew (32 and 38%, respectively). No significant changes were observed after ultrasound treatment. The antioxidant properties of ultrasound processed honeys were insignificantly reduced up to 8%, while total polyphenols content increased by 3–6% in 75% of tested samples. The hydroxymethylfurfural (HMF) content significantly increased after both treatments (from 31 to 40%), however without exceeding the allowable limit.Industrial relevanceHoney crystallization during storage is natural but undesirable serious problem in processing and marketing of the honey. The ultrasound processing shortened the processing time (saved costs), limited the honey biological activity deterioration, and delayed the re-crystallization of processed honeys. Ultrasound processing is a beneficial non-thermal alternative for conventional liquefying of honey by heating.     

Investigation of antibacterial and antifungal properties of tufting carpets containing metal composite yarns

In this research, antimicrobial (antibacterial and antifungal) properties of tufting carpets containing metal/texturized polyester composite yarns were investigated. Carpet contains different yarn groups such as pile yarns, ground warps and wefts. Backing fabric’s warp and weft yarns are suitable for gaining antimicrobial activity because of their placement and low usage amount. Thus, textured polyester yarns were commingled with copper, stainless steel metal wires and silver metalized polyamide yarn. Backing fabrics were produced with four different placements by composite yarns. Antibacterial activity tests were applied to carpet samples according to AATCC 100 standard against K. pneumoniae and S. aureus bacteria. AATCC 30 – Part 3 standard was used for determining antifungal activity against A. niger. Results show that the antibacterial activity increases with increasing in the amount of metal composite yarn in unit area. Carpet samples which include copper or metalized silver composite yarn in all warps showed antibacterial activity about 99%. Moreover, antifungal activity can be provided against A. niger when copper and metalized silver composite yarn is used in all warps of carpet samples.     

食品抗菌包装纸的研究

概述了抗菌食品包装的发展及其抗菌机理,具体介绍几种抗菌包装纸的研究及应用状况,以期能对今后的新型抗菌包装纸的开发有所裨益.     

Evaluation of the antioxidant properties of Mediterranean and tropical fruits compared with common food additives.

Several Mediterranean and tropical fruits have been analyzed in order to assess their antioxidant activity compared with that of common food additives (butylated hydroxyanisole [BHA], butylated hydroxytoluene [BHT] and propyl gallate). Among Mediterranean fruits, red grape and plum were more effective (P < 0.05) scavengers of peroxyl radicals than BHA, BHT, and propyl gallate. Of the tropical fruits, banana was the most effective scavenger of peroxyl radicals. Mediterranean and tropical fruits showed very good scavenger activity against hydroxy radicals (OH*), protecting deoxyribose better than BHA and BHT. The HOCI scavenging ability of Mediterranean fruits tested was, in decreasing order, lemon > plum > apricot > white grape > melon > red grape > mandarin > watermelon > peach > medlar > apple > orange > cherry > strawberry. However, the four varieties of pear were poor scavengers (P < 0.05). Among tropical fruits, the order of efficiency as HOCI scavengers was passion fruit > lime > passiflora > kumquat > avocado > pineapple > physalis > papaya fruit > carambola > mango > banana. All Mediterranean fruits showed an effect on hydrogen peroxide except peach. Tropical fruits also had a strong effect on hydrogen peroxide except avocado, which had no effect. The effect of Mediterranean and tropical fruits on the protection factor of refined olive oil, analyzed by the Rancimat method and compared with common food additives, was clear. Watermelon conferred a significantly (P < 0.05) greater protection than the other Mediterranean fruits. Among tropical fruits, physalis had the most stabilizing effect.     

Evaluation of Chenopodium ambrosioides oil as a potential source of antifungal, antiaflatoxigenic and antioxidant activity

Essential oil extracted from the leaves of Chenopodium ambrosioides Linn. (Chenopodiaceae) was tested against the aflatoxigenic strain of test fungus Aspergillus flavus Link. The oil completely inhibited the mycelial growth at 100 microg/ml. The oil exhibited broad fungitoxic spectrum against Aspergillus niger, Aspergillus fumigatus, Botryodiplodia theobromae, Fusarium oxysporum, Sclerotium rolfsii, Macrophomina phaseolina, Cladosporium cladosporioides, Helminthosporium oryzae and Pythium debaryanum at 100 microg/ml. The oil showed significant efficacy in inhibiting the aflatoxin B1 production by the aflatoxigenic strain of A. flavus. During in vivo investigation it protected stored wheat from different storage fungi for one year. Chenopodium oil also exhibited potent antioxidant activity when tested by ABTS method. All these observations suggest the possible exploitation of the Chenopodium oil as potential botanical fungitoxicant in ecofriendly control of post harvest biodeterioration of food commodities from storage fungi.     

Chemical,antioxidant and antibacterial study of Brazilian fruits

In this study, the antioxidant capability, total phenolic content and antimicrobial activity of ethanolic extracts of seven fruits from the Brazilian Atlantic Forest were evaluated. The conditions for the extraction of crude phenolics from the fruits were determined using an experimental factorial design. Total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH^?) scavenging activity and β‐carotene‐linoleic acid couple oxidation assays were used to evaluate the antioxidant properties of the extracts. In addition, antimicrobial activity was screened using two Gram‐negative bacteria (Escherichia coli and Klebsiella pneumoniae) and one Gram‐positive bacterium (Staphylococcus aureus). All native fruits assayed in this study have high potential as natural antioxidant sources. Among the seven fruits evaluated, Jabuticaba and Uvaia had the highest antioxidant activity in the DPPH^? and of β‐carotene‐linoleic acid coupled oxidation assays. In the biological assay, K. pneumoniae was the most sensitive microorganism to the fruit extracts, and the Jabuticaba extract had a slight inhibitory effect against this Gram‐positive bacterium.     

Hake proteins edible films incorporated with essential oils: Physical,mechanical, antioxidant and antibacterial properties

Physical, mechanical, antioxidant and antimicrobial properties of hake protein films incorporated with citronella, coriander, tarragon and thyme oils were investigated. Dried hake proteins were solubilized at pH 11.0 (protein concentration in film forming solution ca. 0.9%) and glycerol (59% w/w of protein) and 0.25 ml of each essential oil per gram of protein was added. Films obtained were homogeneous and transparent with a yellowish colour. The addition of the different essential oils reduced the water vapour permeability but increased the solubility of films in water. The amount of protein released from the films depended on the oil added. Among all essential oils incorporated-films the thyme oil films exhibited the lowest mechanical properties (puncture force and elongation at break). Conversely, films with thyme oil added presented the highest inhibition against Shewanella putrefaciens. Antioxidant activity of hake protein films generally increased with the incorporation of essential oils as indicated by DPPH radical scavenging activity and reducing power.     

Recent advances in biobased and biodegradable polymer nanocomposites,nanoparticles, and natural antioxidants for antibacterial and antioxidant food packaging applications

Inorganic nanoparticles (NPs) and natural antioxidant compounds are an emerging trend in the food industry. Incorporating these substances in biobased and biodegradable matrices as polysaccharides (e.g., starch, cellulose, and chitosan) and proteins has highlighted the potential in active food packaging applications due to more significant antimicrobial, antioxidant, UV blocking, oxygen scavenging, water vapor permeability effects, and low environmental impact. In recent years, the migration of metal NPs and metal oxides in food contact packaging and their toxicological potential have raised concerns about the safety of the nanomaterials. In this review, we provide a comprehensive overview of the main biobased and biodegradable polymer nanocomposites, inorganic NPs, natural antioxidants, and their potential use in active food packaging. The intrinsic properties of NPs and natural antioxidant actives in packaging materials are evaluated to extend shelf-life, safety, and food quality. Toxicological and safety aspects of inorganic NPs are highlighted to understand the current controversy on applying some nanomaterials in food packaging. The synergism of inorganic NPs and plant-derived natural antioxidant actives (e.g., vitamins, polyphenols, and carotenoids) and essential oils (EOs) potentiated the antibacterial and antioxidant properties of biodegradable nanocomposite films. Biodegradable packaging films based on green NPs—this is biosynthesized from plant extracts–showed suitable mechanical and barrier properties and had a lower environmental impact and offered efficient food protection. Furthermore, AgNPs and TiO₂ NPs released metal ions from packaging into contents insufficiently to cause harm to human cells, which could be helpful to understanding critical gaps and provide progress in the packaging field.     

MTG酶催化接枝的羊毛织物抗菌防霉整理

利用新型生物交联剂微生物谷氨酰胺转氨酶(MTG酶)将ε-聚赖氨酸、溶菌酶和乳铁蛋白接枝到羊毛织物上,实现羊毛织物的抗菌防霉整理,并测试其抗菌、防霉效果.结果表明:对金黄色葡萄球菌,ε-聚赖氨酸接枝羊毛织物的抗菌效果最好,有1.6 mm的抑菌带形成;溶菌酶和乳铁蛋白接枝羊毛织物的抗菌效果较好,但无抑菌带生成.对大肠杆菌,ε-聚赖氨酸接枝羊毛织物有1.75 mm的抑菌带形成,效果最好;乳铁蛋白接枝羊毛织物虽无抑菌带生成,但菌落繁殖受到限制,效果较好;溶菌酶接枝样效果则有限.防霉剂SCJ -950、ε-聚赖氨酸和溶菌酶接枝羊毛织物均有一定的防霉效果.     

Microbial and physiochemical properties of Cheonggukjang fermented using Bacillus strains with antibacterial or antifungal activities

Cheonggukjang was produced with improved functionalities and safety using Bacillus subtilis W42 with an antibacterial activity and B. amyloliquefaciens MJ1-4 with an antifungal activity as starters with coinoculation of B. subtilis W42 and B. amyloliquefaciens (MW Cheonggukjang). Control cheonggukjang was prepared by inoculation of B. subtilis 168 (BS cheonggukjang) or a commercial cheonggukjang prepared using traditional methods (TM cheonggukjang). Cheonggukjang samples were immediately spiked with B. cereus ATCC11778 (1×10⁵ CFU/g of dry soybean) and Penicillium sp. that produced ochratoxin (1×10⁵ spores/g of dry soybean). During 72 h of fermentation at 37°C, total Bacillus counts increased, reaching 10⁹ CFU/g in MW and BS cheonggukjang. Numbers of B. cereus and Penicillium sp. decreased. The largest reduction was observed in MW cheonggukjang. Fungi were not detected after 24 h in MW and BS cheonggukjang. Fibrinolytic activity was detected only from MW cheonggukjang and the antioxidant activity was highest in MW cheonggukjang.     

Evaluation and improvement of antioxidant and antibacterial activities of supercritical extracts from clove buds

For the first time, extracts from clove buds obtained by supercritical carbon dioxide extraction were screened for antioxidant and antibacterial activities. Additionally, antioxidant and antibacterial activities of extracts obtained by the supercritical extraction of the clove bud–oregano leaf mixtures were studied. Supercritical extract of pure clove had the highest eugenol (64%) and total phenolic content (530.56 mg GAE/g_extract). All extracts had antioxidant activity comparable to synthetic antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and formation of peroxides. Presence of 0.6% and 5% of oregano extract in the clove extracts obtained from the clove–oregano plant mixtures improved their antioxidant activity with respect to the extract from pure clove. Clove extract showed moderate antibacterial activities against selected Staphylococcus and Enterococcus bacterial strains. Presence of 50% of the oregano extract improved antibacterial activity of clove extract against all tested strains and resulted in a synergistic antibacterial activity against Methicillin-resistant Staphylococcus haemolyticus strain (MIC ? 1.25 μg/mL). Study demonstrated great potential of supercritical clove extract as natural functional ingredient and the possibility of increasing its antioxidant and antibacterial efficiencies in order to apply lower concentrations and to reduce undesirable flavour notes and toxicological effects in final products.